DEAR DR. BLONZ: I eat a few eggs almost every week. Lately, I'm seeing more types at the store that include omega-3 fats, which I had thought were only in fish. I wanted to know more about this. How much omega-3 do you get in these eggs, compared to what we need? -- T.T., Mesa, Arizona
DEAR T.T.: Some background first: Fats are long chains of carbon atoms. The name "omega-3" refers to the location of the first double bond -- in this case, the third carbon (3) from the end (omega) of the chain.
There are three different essential omega-3 fats in human nutrition: ALA (alpha-linolenic acid), EPA (eicosapentaenoic acid), and DHA (docosahexaenoic acid). They are all considered essential because they are needed to support normal health, and we can't make them on our own.
ALA is in plant oils, including flaxseed, canola, soy and walnut. More well-known omega-3s include the longer-chain EPA and the even-longer-chain DHA, both found in fish and other seafood. Omega-3 fats are often collectively called "fish oils," but this is inaccurate since plant-sourced ALA does not come from fish.
Our metabolism has a chain-lengthening mechanism that allows it to convert ALA into EPA and DHA. This capability is important for vegetarians and for anyone who doesn't eat seafood. However, this "lengthening" mechanism is inefficient, with only a fraction of ALA getting converted to EPA and DHA. While some makes it, most ALA in the diet gets burned for energy. Vegans should pay attention to their ALA intake or consider taking a supplement (more on this at b.link/4bfyqq).
Omega-3-enriched eggs will have a higher content of these fatty acids, but you must read the label to determine the type present in any particular brand. If the hens' feed was enriched with flaxseed meal, the eggs would have increased levels of ALA, and a slight amount does get lengthened into EPA and DHA by the hen's metabolism. Some brands enrich the feed directly with EPA and DHA from fish oil or marine algae. In those instances, the eggs will have higher levels of the longer-chain omega-3s, but still only a fraction of what you get from fish sources. As with any specialty eggs, enriched ones will cost more.
The amount in omega-3 enriched eggs can vary, so, again, read the label; one popular brand provides 125 milligrams per egg, which is only a fraction of that in seafood. The American Heart Association recommends 1 gram daily of DHA and EPA for overall heart health.
For reference, the richest sources of EPA and DHA are cold-water fatty fish such as salmon, mackerel, herring, sardines and anchovies, and other seafood, including oysters and caviar. (For more on fish, including a chart of levels, see b.link/bbv3ze.)
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.